Traction City

In Philip Reeve's Hungry City Chronicles, Traction Cities are vast metropolises built on tiers that are capable of moving on gigantic caterpillar tracks. These cities hunt smaller cities (in order to tear them apart for resources) which in turn hunt towns which in turn also hunt villages and static settlements. This practice is known as Munincipal Darwinism. Traction Cities range in size from enormous metropolises with populations of millions, to tiny hamlets propelled by sails.

There are also aquatic equivalents called "raft-cities" which travel across the oceans hunting smaller raft suburbs and island settlements. Notable Raft Cities include Puerto Angeles, Grimsby, Brighton and Marseille, most of which are coastal ports in the real world. As well as standard traction cities and "raft-cities" there are combinations of raft and traction cities which are called "amphibious cities" such as Turnbridge Wheels, that work as standard traction cities on land until they reach water at which point a series of quick processes to activate underside floatation tanks or hovercraft systems and propulsion devices. There is also a Traction city that travels the skies, by use of light alloys and a nimbus of hydrogen balloons (hydrogen is refered to as lift-gas), called Airhaven. Airhaven is the only Traction City in the books that does not follow Municipal Darwinism - it survives by trading and providing fuel and supplies to passing airships, and since it is airborne it is well out of reach of other cities.

Traction cities in the books are often named after cities in the real world, such as London, Anchorage or Paris, and sometimes their names have been slightly modified for comedic effect; for example, Tunbridge Wells has been named 'Tumbridge Wheels'.

Traction Cities were first formed by an engineer from London (which subsequently became the first of its kind) after the Sixty Minute War. After the devastating war, the world collapsed into a post apocalyptic state, and immense geological upheaval (such as earthquakes, tidal waves and glaciers) threatened the world's surviving cities. In order to survive, urban areas were mobilised into vast vehicles that move on caterpillar tracks. Naturally this required vast amounts of fuel, and as the earth became stripped of its natural resources, cities resorted to the practice of Municipal Darwinism and began to consume each other for energy.

The most common method of travel and trade between cities is by airship. Railway is impossible due to the mobile nature of Traction Cities, and seaborne ships would be easy prey for any raft-cities.

At the beginning of the series, the most common area for Traction Cities to be found is Europe, which is now a muddy wasteland called the 'Great Hunting Ground'. They are also prevalent in South America (known as Nuevo Maya) and Antarctica (where they drill for oil); North America is a nuclear wasteland, Australia are not specified and Asia and much of Africa is the stronghold of the Anti-Traction League and later the Green Storm.